title: Folate analogues altered in the C9-N10 bridge region. 18. Synthesis and antitumor evaluation of 11-oxahomoaminopterin and related compounds.
abstract: The chemical synthesis of 11-oxahomoaminopterin (1) has been carried out using procedures which were also found to be applicable to the synthesis of 11-oxahomofolic acid (2). Reaction of 1-bromo-4-[p-(caarbomethoxy)phenoxy]-2-butanone (10) with sodium azide gave 1-azido-4-[p-(carbomethoxy)phenoxy]-2-butanone (11). Protection of the carbonyl group of 11 as the ethylene ketal and subsequent base hydrolysis of the product gave 1-azido-4-(p-carboxyphenoxy)-2-butanone ketal (13). The glutamate conjugate 14 was prepared from 13 by the isobutyl chloroformate method and was hydrogenated to diethyl N-[(alpha-amino-2-oxo-4-butanoyl)-p-anisoyl]-L-glutamate ketal (15). Reaction of 15 with 6-chloro-2,4-diamino-5-nitropyrimidine (16) and 2-amino-6-chloro-4-hydroxy-5-nitropyrimidine (17) and deprotection of the corresponding products gave the intermediates 18 and 19, which were elaborated to 1 and 2 using a series of steps involving deprotection, dithionite reduction, cyclization, oxidation, and hydrolysis. Although 11-oxahomoaminopterin showed antifolate activity against two folate-requiring microorganisms and inhibited Lactobacillus casei DHFR, it was inactive against L-1210 leukemia in mice at a maximum dose of 48 mg/kg. Compound Lactobacillus casei DHFR, it was inactive against L-1210 leukemia in mice at a maximum dose of 48 mg/kg. Compound 1 was also tested for its ability to be transported via the methotrexate transport system using the L-1210 and Ehrlich tumor cell lines, and these results are compared with those of related analogues. The growth inhibitory activity of 1 in the L-1210 cell lines in culture was found to be 15 times weaker than that of methotrexate.
mesh_terms: D000630:Aminopterin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis*; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D007780:Lacticaseibacillus casei / Q000187:drug effects; D007939:Leukemia L1210 / Q000188:drug therapy; D051379:Mice; D013291:Streptococcus / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; C032417:11-oxahomoaminopterin; D000630:Aminopterin